Rat Poison May Not Be Only Dog Food Recall Culprit

ASPCA suggests other contaminants may be behind the dog food recall.

ASPCA suggests other contaminants may be behind the dog food recall.

Although aminopterin, an experimental cancer drug used as rodenticide in some foreign countries, was found in the recalled dog food from Canadian-based Menu Foods on March 16, other possible contaminants are not being ruled out.

The U.S. Food and Drug Administration and American Society for Prevention of Cruelty to Animals both say other contaminants are possible. In the last week, the ASPCA says, its Animal Poison Control Center has received a flood of cat cases related to the recall, but the animals’ symptoms are not consistent with a diagnosis of ingesting aminopterin.

“We’ve seen reports coming in from all around the country that animals that were eating the contaminated foods are definitely suffering from renal failure. But the data that we’ve been collecting do not conclusively prove this connection,” said veterinary toxicologist Steven Hansen, DVM, DABVT, the poison control center’s senior vice president.

Hansen and the ASPCA are urging veterinarians and investigators to continue their analysis of the recalled pet food for additional contaminants.

Little is known about the drug’s effects on animals, but the ASPCA and other veterinarians are using what they know about this class of drugs to determine their response. “Aminopterin has been used to treat cancer in people, since it is able to disrupt rapidly-growing cells,” Hansen said.

“In animals, it should result in effects that mimic this function, and these include bloody diarrhea, bone marrow suppression, abortion and birth defects. Further, renal damage — which has been seen in the affected animals — can occur at high doses.

“However, to be consistent with the effects of aminopterin, we should also be seeing a significant number of affected pets showing the accompanying signs of severe intestinal damage, as well as bone marrow suppression, including ‘leukopenia,’ which is a serious reduction in white blood cells,” Hansen said.

The FDA’s top veterinarian, Stephen F. Sundlof, DVM, also sounded a cautious note about the aminopterin discovery. “While we are very interested in the discovery of this compound, we want to make sure all possible causes have been ruled out before confirming any one particular cause,” he said.